Julian Lewis: Even if the Assad regime fell tomorrow, the Syrian Government could give us no guarantee at all that their chemical weapon stocks would not fall into the hands of the thousands of al-Qaeda fighters who are fighting alongside the opposition—and it took just a couple of dozen people to organise 9/11. Would not a more sensible strategy be to work with the Russians and to try to get a ceasefire rather than to remain obsessed with overthrowing the regime?